The definition of an isotope is illustrated using the three isotopes of carbon. The three isotopes of hydrogen are discussed as exceptions.

Learners read about lab equipment and basic safety measures. In a quiz, they view photos and determine if the lab technicians pictured are using safe practices.

Students read about the basic organization and structure of the periodic table of elements. By clicking on the symbol, they can read that element's atomic number and weight. In an exercise, students identify elements as belonging to a group, a period, or neither.

Learners calculate gas density from the standard molar volume and observe how the density increases with the increasing molecular weight of the gas.

Students use the pyramid method to solve percent problems. The pyramid grid provides a visual way to set up the equation.

Students read how to determine and calculate the dry density for a given sample of soil or aggregate based on the mass-volume relationship.

Students read how to determine and calculate the saturated density for a given sample of soil or aggregate, based on the mass-volume relationship. Practice problems complete the activity.

Learners follow a four-step process to determine the empirical formula of a compound from the masses of its constituent elements. The molecular formula is determined in a fifth step using the molecular weight of the compound.

Students interpret pie chart information and identify the parts of a chart in an interactive exercise.

Percent word problems

A kids game about Chemicals and compounds

Recall the ideas about Chemistry

Science Review IV Midterm